Abstract Nonunion of a proximal tibial stress fracture is rare and can be difficult to manage, especially if associated with ipsilateral gonarthritis. Three patients with nonunion of a proximal tibial stress fracture adjacent to an arthritic knee joint were managed by performing simultaneous total knee arthroplasty and internal fixation of the fracture site. The technique involved performing a total knee arthroplasty with angular correction at the site of the extra-articular and intra-articular deformity, bone grafting of the nonunion site, and stabilization of the fracture with a long uncemented intramedullary stemmed tibial component and a unicortical plate. Fibular ostectomy was required during the index surgery in 2 cases to achieve the desired angular correction. In all 3 patients, healing of the nonunion site and limb realignment was achieved. There were no complications or infections associated with the surgery. All patients progressed to full weight bearing at 3 months and had clinical and radiographic union of the nonunion site at 6 months.